Discussion

Tuna confit in pork fat...

I'm thinking of rendering some leftover guanciale and using the fat to confit some tuna steaks for a "tunafish" sandwich (though I hate canned tuna, so the need to replicate the texture is not there). I'm curious if anyone has any suggestions about time and temperature for cooking (I'm going to sous vide in the fat) - if cooking a tuna steak, I'd probably cook to 110deg, and I don't particularly need to pasteurize in this instance, so it's purely a question of texture. Wonder what would happen if I cooked it at 110 for an hour or three in the pork fat?

Most tuna confit I see is cooked at around 150deg and only for 5-10 minutes, but again, I think that's a pasteurization thing, any suggestions on what temp would be best and what texture would be best to shoot for here?

an hour, or worse yet three, is complete overkill. the tuna will be falling apart. there is almost no fat and very little connective tissue to hold the fish together. are you wanting to cook it through? that will take less than 30 minutes even at the slowest heat.

i often confit sword/salmon/tuna in olive oil. not wanting it cooked well done, it takes less than 15 minutes.

I was speaking of pasteurization in the sense that most confits are made to be preserved, and I don't plan on keeping any of this around, so I see no need for that high of a heat. Well, it may fall apart a little I'm sure that will happen, but that's kind of what I'm going for anyway. More like tuna rillettes, then, I guess... I'll see how it goes, but I'm going to go for an hour to really try to get the flavor of the pork fat into the tuna and see what happens... I've seen several blogs where people employed similar methods with reasonable looking results, so might as well give it a spin...

It's both. The anaerobic environment is important. But so is the fact that you have effectively pasteurized the meat in the oil before storage (try keeping raw meat under oil and see what it looks like after a month or two). Also, the salt cure is very important for longer term storage because it protects from botulism.

I've done things like this with sous vide, cooking salmon confit at very low temperature.

You are correct that you are not necessarily aiming for pasteurization. However, keep in mind that the fish is essentially sashimi, and should not be served to immunocompromised or otherwise vulnerable people.

You don't need to cook it 3 hours. You'll get the same effect just cooking it through. In my experience, you won't get any more flavor from the cooking fat when confit-ing for a long time than you would from a shorter cooking time. On top of that, the longer you cook the fish at that temperature, the more dangerous it is from a microbiological perspective. 110 isn't far from the reproductive sweet spot for a lot of bacteria.

Obviously you'd want to serve it quickly and not store the fish afterward.

Incidentally, you're working very near the melting temperature of some pork fats. This may pose engineering problems that you aren't expecting. I don't think I've ever confit'd in pork fat at a temperature so low, so it's a little hard to guide you.

Yeah, I think I'm gonna do it at 140 for 10-15 minutes then... I was really only going for the long time to try to infuse more pork flavor from the fat, but if that's not going to work well, I'll just do it the normal way... Think I'll get a better texture at 140 than 110 anyway for what I'm going for... Thanks for the advice!

At that temp, if you have a reasonably thick tuna steak (room temp before cooking), you should get a steak that is just a little less done in the center than at the outsides. This can be a very appealing effect. The downside is it may take a little experimentation and experience to figure out exactly how long to cook a tuna steak of any given thickness to achieve the exact effect you want.

You should also dodge any potential problems with the pork fat not being fully melted.

I actually ended up cooking it at 118 degrees for 1 hour, 15 mins and it came out far better than I could have hoped (I ditched the sandwich and went with a Japanese prep). Very rare center, pork fat gave a nice, but not overwhelming flavor, and the texture was quite firm still (easily sliced) - very nice...